Selector for telephone plants.



e. GRABE'. SELECTOR FOR TELEPHONE PLANTS.

' APPLICATION FILED OCT- l5. 1913. 4 1., 1 61,126. Y Patented Ngov. 23, 1915.

Mai

M ns parenthesis-n j Gnone amen, or uixfoiaassnn, nnan. BERLIN, GERMANY, assrsnon ro SIEMENS & HALsKn A.-G. 01E BERLIN, GERMANY, a conronnrron or GERMANY.

' snnno'ron non TELEPHONE PLANTS.

Patented Nov. 23, 1915.

ap lication filed October 15, 1913. Serial No. 795,285.

To all whom it may as-can Be'it knownthat I, Gnonc Gi na, a Germancitizen, and resident of N kolasse, near Berlin, Germany, have invented certa n 'new and useful improvements in Selectors for Telephone Plants, of which the following isa specification, My invention in brief relatesto a selector for establishing connections intelephone plants lay having the adjusting member retained at a desired contact by means of a locking mechanism which is mechanically bro fught into locking position and retained therein by a change of the magnetic condl- 'tion of the test electro-magnet.

The-stopping and locking of automatic selectors for telephone plants for estabhsh: ing connections in case of certain kinds of selectors is accomplished in the manner that upon the contacting of the adjusting mem her with the contact of a desired line, for instance a free connecting line, a counterforce is generated by the change of magnetic condition of magnets, preferably of the test magnets, effecting the locking, said cotnter-force being in equilibrium to the driving force which is increased by the inertia of the moved masses and whlch brings the selector to a standstill. Such structure is for instance illustrated in Figure 2 of U. S. Patent No. 97 5,105. In case of large selectors this force to be exerted by the magnet assumes a relatively considerable quantity, which is all the more important since it must increase to its maximum during the contacting time between the adjusting member and a contact. In high-speed selectors this time will necessarily limit the speed of rotation, as the adjusting memoer would leave the respectiven i entact before the test magnet would be enabled to attract and re tain its armature which initiates the testing and locking procedures.

According to this invention a locking of the selector will be enabled at the beginning of the magnetic change of the test magnet independently of the field strength of the latter at the time attained, in that the looking member is brought mechanically, for instance by the driving force .or moving the selector, into the-locking pos-a-ion, and

retained inthis position by said test magnet I upon the-contacting the adjusting memstood by j tomy present invention.

reference to the accompanying drawings, WlllCll show in a diagrammatic manner a few forms of selectors according Fig, 1 shows a pre-selector according to my inventlon,

several figures of the drawings I have shown a coupling disk 2 which is :mounted on'the axle I of a pro-selector provided with contact arms and a series of fixed contacts, said coupling disk forming the one part of a magnetic coupling for transmitting the motion of a permanently rotating axle 3, which is provided perpendicularly to the axis of the selector. A disk 4 is mounted upon said axle 3 and is formed as a magnet pole, said disk being mounted to I ing rotation before the poleof the electromagnet or coupling magnet 5, so thatqit will upon excitation. of the magnet r5 contact with the disk 2 and carry the same with it in the direction of the arrow. Upon the, axle 1 of the selector a ratchet wheeljtl :is' mounted having an escapement in the of the pawl 7, said pawl being projze ed} with a. projecting part 8 forming the a r a] ture of a separating relay T. This part 8 is retained in its position of rest immediately beforeflthe pole of the relay T by means of a nose 14: of, a lever with several arms rotatable around a point 10,which lever opcrates as 'the armaturefioffianr electrormagnet at one nd of which a spring 11 exerts pulling force against the attracting force of" the magnet of said relay R according to the drawing. The one arm 12 of the armature 9 extends in its position of rest into one of a number of recesses 13 provided upon a disk 15, which is mounted upon the axle of the selector. These recesses which are provided at even intervals at the periphery of the disk 15 will determine the zero-positions of, the selector and possess preferably a dimension extending beyond the mean-distance between two adjustments of the adjusting mem-. ber, in order that the lever after catching cannot again jump on account of the inertia of the locking mechanism and thereby throwing the adjusting member ofthe selector beyond the zero-point. By exciting the coupling magnet 5 and the relay R th selector will start to run whereby the pawl 7 "takes the receiver off, the relay (call relay.)

will be excited, a circuit being formed over ground? back contact 25,: of the 1 separating relay-T, subscriber apparatus ',-X,back con' tact t winding of the relay R,'battery and of the coupling magnet'fi and the selector 3 y will start to operate. .As the armature 9 re-' 'leas'es the pawi 7 'onexcitationpf the. relay R this pawl'w ll be.'enabledvto freely oscillate; The excited relay R after-sufficient excitation will also close-its working contact 1 whereuponthe separating relay will work inv vthe knownmanner also as .atest relay. If

theltestingf arm of the selector now meets a free line, a circuit will be closed over. ground, battery, working contact 1",, winding of therelay T], testing arinC, back contact m, relay Q;and ground,.the test relay T bein excited up to its maximum during the' 1 "auction of the testing arm 0 overthe respec- "tise centact. 'At the j same time by the ratchet wheel 6 the projection 8 of. the pawl 7 will be moved in a direction toward the test relay T. If the selector armnow has arrived at the middle part of the desired contact, then also according to-the pitch of the pawl, the armature 8 will just be moved in proximity to the pole of thfe relay T, in the moment of strongest magnetic action;

thus locking of the selector Wlll take place. i It is not necessary that in this moment the current in the winding of the relay T have reached its full value, becausethe retaining of an armature upon contacting with the pole may be effected by a current having an essentially smaller value than if the armature had t6 be attracted by the pole from a greater distance. The relay T causing the testing will close in case of-a sufficiently strong field its working contact whereby a part of its resistance will be short-circuited and the connecting line locked in the known manner for other pre-selectors. Furtherni'or'e the relay T will open the back contacts t and t whereby the relay R and therewith also the coupling magnet 5 will become in- The. deenergizing of the relays operative. R and 5 takes an essentially longer time than would be necessary for the selector to pass the desired contact. By the retention of the projection 8 at the relay T in case of contact with the calling line the selector. arm will be retained after meeting a desired contact, although the selector will still be further driven for some time. The release of the.

selector, now, is accomplished by opening of the contact 'm, in a switching apparatus which is arranged back of the pre-selector,

6, magnet 5 and ground. By this the selector I again will be rotated until the arm 12 passing along the circumference of the diskl5 will fall .mto the next recess 13 and until the nose 14 will lock the part 8. By this also at ground. The relay Rcloses at T the circu t When taking off the receiver therefore at a the subscriber station X no current for exciting the relay R will be caused to flow.

In the arrangement of the selector shown in Fig. 3 the pawl 7 is kept in its locking position by action of a spring 11,, while its release will be caused by the excitation of the test relay P which will compensate by the attraction-of the armature 8 provided at the pawl 7 the action of the spring so that the escapement will freely play. The selector may be advantageously operated by means of pulleys, whereby the permanently rotating cord 16 will slide over the pulley 2 in case the same is locked by the pawl 7. The escapement and the test relay are so arranged that the position of the contact arms upon the middle of a contact will correspond to the end-position of the locking member 7 which is at a distance from the pole of the relay P. The head contact 7: of the selector will immediately be opened by a recess or v groove 13 arranged in the disk 15, for one spring of the contact 70 during rotation of the selector axle Z will slide upon the circumference of the disk 15 and thereby keep the head contact is closed as long as the selector is in a condition off from the zero-position.

The mode of operation of the arrangement shown in Fig. 4 for the adjustment of a selector according to Fig. 3 is as follows: If the subscriber X takes oif the receiver the excited circuit of the test relay P,will be closed over ground, back contact t subscriber apparatus X, back contact 25 back contact of the contact arm C, back contact 25 winding 79, of'the test magnet P, battery and ground. By the attracting force of the relay P the tensional force of the spring 11 will be counteracted and the selector will start to rotate, the time for the field strength notice I terial in this case. For explanation let it be assumed that the two first contacts of the pro-selector are otherwise occupied by having the testing strands connected to ground the known manner. Consequently the re lay P will remain excited if the arm C touches the first and second contacts, so that it will disconnect the talking contacts A and B from the subscriber line of the subscriber Upon the arm C makin contact with the free third contact the'relay will become inoperative, the power of the spring 11 will come into action and press the pawl 7 into a tooth of the ratchet'wheel 6 so that the selector will be retained in position. ,The drop ofmagnetism in the relay P will begin, when the contact arm leaves the occupied contact of the-second connecting line, that is to say beforetne contact. arms of the selector have reached the middle of the third con"- tact. Upon contacting with thefree con -tact the escapement will be moved away 75 from the pole of the magnet P. If therefore the field strength. of the magnet P does not instantly disappear, it will certainly be weakened tosuch'an extent -that the action of the spring 11,- will overpower and retain the pawl 7 in its locking position. If'now the armature of the relay P has fallen ofi, a circuit will be established over ground, battery, back contact windinggtl of'the sep aratin relay T, winding pg of the test relay selector arm D, resistance 'w of the succeeding'selector, for instance the group" selector, and ground; Inthis circuit the sep arating relay T will-be excited, the relay will, however, remain inoperative, therelay T disconnecting at t, and t the calling circuits from the line and connecting the testing line toground by changingover at the contact thus locking the connecting line for other pro-selectors.

' For releasing the selector at the group selector the resistance 10 will be short-circuited in the known ma er'byjclosing the con tact m. By this the current in the circuit over the winding 77 will be so reinforced that the relay P will now be excitedover this winding. By closing the working contact 72 of Pa holding circuit will be established for both relay P and T over ground, head contact it, working contacts t and p winding t,,- of the separating relay T, winding p,

of the test relay P, battery and ground,so that by the now established excitation of. the relay P the escapement 7 will again be enabled to play freely by reason of the action of the spring 11,, being counteracted.- As soon as the head contact, however, is opened by the snapping of one of its springs into a recess13 of the disk 15, both relays will lose their excitation and all parts of the selector will now again be in the zero-position. r

' prising ad ustmg member in a contacting positfiTmt lt the subscriber X becalled from a line selector, the aratingrelayT will be excited in the known manner over the testing strand of. of the line selector, its winding t back contact 10 battery and ground. Thereby at t, and tthe calling circuits will be discoimccted from the pre-selector.

I therefore claim as new and desire to secure by Letters Patent of the 1 Unlted States: v

14A selector for telephonesystems, comprising a locking device for retaining the ad,- justing member in a contacting position, mechanical means for bringing said locking device into locking position by the moving force for said adjusting member, and maglocking member when in locking position.

2. Afselector for telephone systems, coma locking device for retaining the mechanical means for bringing said locking device into locking position by themoving force for said adjustin member, and magnetic means" for' immedlately operating said lockingmember when in. locking position and in the moment of contact between said adjusting member and the respective contact.

' {5; A selector for telephone systems, comprising an adjusting member, a locking de- VICG fOI retaining said adjusting member in acontacting position, mechanical means for bringing said locking member into locking position by the moving force for said ad.-

ustmgmember, .a test magnet forimmedi- .ate'ly operating'said locking member when contacting with adesired contact, and means for varying the magnetic condition of said test magnet.

4a A selector for telephone systems, com-- prising a locking device for retaining the adustmg member in contacting position, mechanical means for bringing said locking device into locln'n position by the moving 'force for said ad usting-member, magnetic means for immediately operatingisaid locking member when in locking position, mean for energizing o'r denergizing said magnetic means in the moment of contacting of the adjusting-member with the respective contact, said mechanical and. magnetic means being adapted to cause said locking device, when locking, to be in a limitposition before a magnetic pole.

5. A selector with a plurality of zero-positions for telephone systems, comprising a locking device for retaining the adjusting member in a contacting position, mechanical means for bringing said locking device into locking position by the moving force for sa1d'ad usting member, magnetic means for immediately operating'said locking member when in'locking position, members for determmmg the zero-posltions which are of a IOU greater dimension than the mean distance between two proximate positions of the adjusting member, for preventing the latter to be thrown beyond a zero-position by rea- -son of the inertia of the locking mechanism.

6. A telephone selector with a plurality of zero-positions, comprising a locking device for retaining the adjusting member in a contacting position, mechanical means for .bringing'said locking device into locking "position by :the moving force for said adjusting member, magneticmeans for immediately' operating said locking member when in locking position, a mechanism'for deter mining the zero-position which is greaterthan the mean distance between two proxif mate positions of the adjusting member, for preventing the latter from being thrown beyond a zero-positionth'rough the inertia ofsaid locking device. 7 A selector for telephone systems, comprising a locking device for retaining thead j usting member in a contacting position, mechanieal means for bringing said locking device into locking position by the moving force for said adjusting member, magnetic means for immediately operating saidlocking member when in locking position and in the moment of a desired contact of said ad justing member, a mechanism for determin 1 ing a zero-position, said mechanism being larger than the mean distance between two proximaterpositions of the adjusting'meim ber, for-preventing the'latter from being thrown beyond a zero-position through the inertiaof the locking mechanism.

8. A selector for telephone systems, comtance between two proximate positions of the adjusting member, for the purpose of preventing the latter from being thrown beyond a zero-position through the inertia of the locking mechanism.-

9. A selector for telephone systems, comprising a locking device for the adjusting member, mechanical means for causing said locking device to come into locking position by the driving force of said adjusting member,'a test magnet in immediate cooperation with said locking member, means for varying'the magnetic condition of said test magnet, and means for producing a plurality "of zero-positions, said latter means being dimensi'oned so as to be larger than the mean distance between two proximate positions of i said. adjusting member.

In witness whereof I have hereunto set my signature in the presence of two,subscribing witnesses.

GEORG GRABE.

Witnesses:

-Wonnnamn HAUPT, HENRY HASPER.

Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents Washington, D. O. 

